NANJING, Aug. 25 (Xinhua) -- Lu Xinning, mother of a four-year-old, feels awkward explaining to her son that he has to revise the knowledge he has just acquired about the solar system.

    The boy learned from his mother that our solar system had nine planets.

    But this statement is now obsolete, as on Thursday afternoon about 2,500 astronomers from 75 nations voted in Prague to deprive puny Pluto of its planetary status under a new universal definition of a planet.

    Sixty-one Chinese astronomers took part in the vote sponsored by the International Astronomical Union (IAU), the official arbiter of heavenly objects. It is reported that they had different opinions about the new definition.

    The issue has aroused interest and bewilderment in China, which has been carrying out astronomical research for more than two thousand years.

    Some say the IAU's resolution "reflects modern understanding of the solar system", while others say they feel sorry about Pluto's demotion. Teachers are anxious as textbooks have been printed and released to the remotest corner of the country for schoolchildren who are ready to start a new semester in a week. Yet the textbooks express the out-of-date position about the number of planets in the solar system.

    Wang Sichao, a planet expert with the Zijinshan Astronomical Observatory based in Nanjing, capital city of east China's Jiangsu Province, said, "The demotion is a scientific result and it reflects the current understanding of humankind about the solar system."

    He said the question about how many planets there are in the solar system often appears in surveys of the scientific awareness of Chinese people. The scientific knowledge of the citizenry is highly important to a nation with the world's largest population and which is striving for sustainable economic and social development, he added.

    Zhao Zhiheng, a member of the Astronomy Association from Tianjin, suggested that primary- and middle-school teachers be trained in the revised knowledge, and that media carry more stories to let more people know about the revision as soon as possible.

    But some are nostalgic. "I just cannot accept the downgrading of Pluto," said Zhu Hao, an office worker at a Sino-foreign joint-venture enterprise in Nanjing.

    "When I was a kid, I learnt that the solar system had nine planets. Suddenly one of them has been kicked out. I can't imagine it," Zhu said.

    China boasts the world's earliest records of solar and lunar eclipses and the richest and most systematic documents concerning the observation of celestial phenomena.

    China was also the first country to use equatorial coordination in astronomical observation and the first to record the Halley's comet.

    China maintained its astronomical traditions until the Yuan Dynasty (1271-1368) when astronomy began to fall into neglect. The discipline has regained its luster over the past few decades. Now China has begun to carry out its own deep space missions and is set to join a worldwide planetary probe.

    Wang Sichao said IAU's decision will positively influence the astronomical sector and the space industry in China. "We must first get a clear definition of planets and the solar system, then we can carry out planetary probe missions in a better way." Enditem